Inositol derivatives for use in pathological crystallization

ABSTRACT

The present invention relates to inositol derivatives covalently modified with one, two or three solubility functions, particularly polyethylene glycol moieties, for use in therapy or prevention of conditions related to pathological calcium crystallization, such as cardiovascular calcifications, nephrocalcinosis, calcinosis cutis, chondrocalcinosis and kidney stones.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Continuation-in-Part of U.S. patent application Ser. No. 16/060,980, filed Jun. 11, 2018, which is the US National Stage of International Patent Application No. PCT/EP2016/080657, filed Dec. 12, 2016, and which in turn claims priority to European Patent Application Nos. 16173422.3, filed Jun. 7, 2016, 16164299.6, filed Apr. 7, 2016, and 15199682.4, filed Dec. 11, 2015. The contents of the foregoing patent applications are incorporated by reference herein in their entirety.

FIELD

The present invention relates to the use of pharmaceutical compounds for treating or preventing conditions related to pathological calcium crystallization.

BACKGROUND

Patients with chronic kidney disease (CKD) suffer from accelerated mineral deposition in soft tissues, in particular in the vascular system, due to a loss in homeostasis of factors that regulate biomineralization processes in the body. Such deposits lead to stiffening of arterial walls, which ultimately leads to increased blood pressure, left ventricular hypertrophy, reduced coronary blood flow, compromised endothelial function and damage to the microcirculation in the kidneys and brain. As a result, all-cause mortality of CKD patients increases exponentially as renal function decreases.

Physiological calcium and phosphate concentrations in the blood are close to supersaturation. Blood components such as fetuin-A interact with calcium and phosphate to form soluble nanoparticles termed calciprotein particles (CPPs) that prevent precipitation and resultant calcification under normal conditions. So-called primary CPPs are amorphous and have a hydrodynamic radius of typically less than 100 nm and mature with time to reorganize into crystalline secondary CPPs that have a hydrodynamic radius of more than 100 nm. Secondary CPPs are subsequently thought to progress to calcification and to initiate pathological responses.

A pharmaceutical agent capable of reducing the propensity for progression of primary CPPs to secondary CPPs, and hence ultimately capable of reducing pathological crystallization, would therefore be of significant therapeutic value. There is, to date, no approved or clinically validated therapy for the reduction or prevention of vascular calcifications.

Thus, the problem underlying the present invention is to provide an efficacious pharmacological intervention for reducing pathological crystallization. This problem is solved by the subject matter of the independent claims.

SUMMARY

The present invention relates to the use of inositol phosphates, sulfates, and/or thiophosphates with or without covalent addition of poly(ethylene glycol) (PEG) or polyglycerol, in preventing or reducing pathological crystallization in soft tissues and conditions related to and developing from such pathological crystallization. Non-limiting examples of such conditions are selected from the group consisting of coronary artery disease, vascular stiffening, valvular calcification, nephrocalcinosis, calcinosis cutis, kidney stones, chondrocalcinosis, osteoporosis, myocardial infarction, cardiovascular mortality, progression of chronic kidney disease, failure of renal transplant grafts, peripheral arterial disease, critical limb ischemia, calciphylaxis, general arterial calcification of infancy, aortic stenosis, atherosclerosis, pseudogout, primary hyperoxaluria, pseudoxanthoma elasticum, cardiac hypertrophy, heart failure, arrhythmia, aneurysm, valvular stenosis, aortic regurgitation, mitral stenosis, mitral regurgitation, stroke, and cognitive function.

According to a first aspect of the invention, a compound described by a general formula (I)

is provided for use in therapy or prevention of conditions related to pathological calcium crystallization, wherein

-   -   Z is (CHX)_(p)CHX(CHX)_(q);     -   p and q each independently from the other have a value from 0 to         2, with the proviso that (p+q) has a value of 0, 1 or 2;     -   one or two or three X can be R¹ and the remaining X         independently from each other are selected from OPO₃ ²⁻, OPSO₂         ²⁻, and OSO₃ ⁻, with the proviso that not all X are OPO₃ ²⁻ and         not all X are OSO₃ ⁻; and     -   R¹ comprises a solubility function R² selected from the group         including         -   a polyethylene glycol or         -   a polyglycerol.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows calciprotein particle (CPP) maturation time in human serum according to the test described in Pasch et al. JASN 2012. The y-axis indicates the half-maximal transition time (T₅₀) in minutes of primary CPPs to secondary CPPs. IP6: myo-inositol hexakisphosphate (Biosynth); IS6: myo-inositol hexakissulfate (Sigma); IP2S4: 4,6-di-(O-phosphate)-myo-inositol 1,2,3,5-tetra-O-sulfate; IT2S4: 4,6-di-(O-thiophosphate)-myo-inositol 1,2,3,5-tetra-O-sulfate; IP5-PEG: 2-PEG(2000)-myo-inositol pentakisphosphate.

FIG. 2 shows the result of a determination of calciprotein particle (CPP) maturation time in human serum according to a similar test as in FIG. 1 (with the test compounds added to the reaction mixture last).

DETAILED DESCRIPTION

There is abundant evidence that vascular calcification is associated with cardiovascular diseases. As described in the following reports, there are also reasons to assume that vascular calcification is the primary cause for certain cardiovascular diseases and that treating vascular calcification in the early stages of the disease can lead to an improved condition of the cardiovascular system.

Cho et al. (J Hypertens. 2015 August; 33(8):1633-41.) studies aortic calcification in elderly men with hypertension. The aim of this study is to investigate the relationship between aortic calcification, arterial stiffening, left ventricular hypertrophy, and diastolic dysfunction. Noncontrast computed tomography (CT) is used for the generation of the aorta calcium score (ACS) and brachial-ankle pulse wave velocity (baPWV) is measured to determine systemic arterial stiffness. A clear association between heavy aortic calcification, resultant arterial stiffening and left ventricular hypertrophy or diastolic dysfunction is shown, even after adjusting for various clinical variables. Only the amount of the aortic calcium deposition reflected by the calcium scores showed a significant independent correlation with E′ velocity, which is a marker of the function of the left ventricle of the heart. Aortic calcification is speculated to underlie left ventricular hypertrophy and diastolic dysfunction in these patients. Of note, the studied population had no serious chronic kidney disease.

Cheng et al. (Pulse (Basel). 2018 March; 5(1-4):144-153.) reviews the role of vascular calcification in heart failure and cognitive decline. One study (Henry et al. Kidney Int 2002; 62: 1402-1407.) shows that renal function is inversely associated with cardiovascular and all-cause mortality and vascular calcification is the major cause of cardiovascular disease in patients with chronic kidney disease (CKD). The authors state that vascular calcification may also enhance arterial stiffness and render arterial stiffness less reversible. The authors speculate that once arterial stiffness or vascular calcification has developed, it may be less likely to stop the ongoing pathophysiology of heart failure. To quantify the interplay between arteries and heart, an index of ventriculo-arterial coupling has been mathematically modelled. The utilization of this ventriculoarterial coupling index, Ea/Ees, could assist in understanding the impact of vascular calcification on cardiac performance. The authors conclude that earlier intervention targeting vascular calcification may benefit the patients with heart failure. Understanding the pathophysiology consequence of vascular calcification may help to improve the management of patients with atherosclerosis, accelerated arterial stiffness, hypertension, and heart failure with preserved ejection fraction.

Di lorio et al. (Kidney Blood Press Res. 2011; 34(3):180-7.) conducted a study on coronary artery calcification progression in 132 middle-aged hemodialysis patients. Coronary artery calcification (CAC), 12-lead ECG and pulse wave velocity (PWV) were assessed at baseline and study completion and statistically evaluated. The authors find that vascular calcification is a marker of vasculopathy and appears to be associated with cardiac repolarization and arterial stiffness abnormalities in patients undergoing maintenance dialysis. A significant change in CAC burden was associated with changes in arterial stiffness and cardiac repolarization and CAC progression was associated with a significantly greater increase in PWV and cardiac repolarization at study completion. The authors conclude that CAC progression is associated with a progressive deterioration of parameters of arterial stiffness and cardiac repolarization. Patients experiencing CAC progression were at significantly greater risk of experiencing a simultaneous deterioration of markers of arterial compliance and cardiac repolarization. Taken together, these results suggest that coronary calcifications are associated with stiffness of large central arteries and cardiac repolarization defects.

Dweck et al. (J Am Coll Cardiol. 2012 Nov. 6; 60(19):1854-63.) reviews the pathophysiology of aortic stenosis with respect to both the valve and the myocardium. In particular, the authors focus on the role of inflammation, fibrosis, and calcification in progressive valve narrowing and then examine the development of left ventricular hypertrophy, its subsequent decompensation, and the transition to heart failure. Aortic stenosis is characterized by progressive aortic valve narrowing and secondary left ventricular hypertrophy. Valve calcification plays a key role in the development of aortic stenosis and can be quantified using computed tomography. The degree of valvular calcification correlates with valve severity, disease progression, and the development of symptoms and adverse events. In one-sixth of patients with sclerosis, the calcification process accelerates, hemodynamic obstruction ensues, and the valve becomes stenotic. This progression is thought to be driven by the differentiation of myofibroblasts into osteoblasts. Calcification is composed of nodules containing hydroxyapatite deposited on a bonelike matrix of collagen, osteopontin, and other bone matrix proteins. Calcification is the critical process in determining the progression of aortic valve stenosis and is therefore likely to be a crucial treatment target. Calcification is believed to be the predominant mechanism by which progressive valve narrowing occurs.

Forsythe et al. (J Am Coll Cardiol. 2018 Feb. 6; 71(5):513-523.) assessed whether 18F-NaF positron emission tomography (PET) and computed tomography (CT) predicts AAA growth and clinical outcomes in patients with abdominal aortic aneurysm (AAA). Fluorine-18—sodium fluoride (18F-NaF) uptake is a marker of active vascular calcification associated with high-risk atherosclerotic plaque. The positron-emitting radiotracer 18F-sodium fluoride (18F-NaF) can identify areas of early microcalcification. Fluorine-18-NaF uptake was increased in AAA compared with nonaneurysmal regions within the same aorta and aortas of control subjects. Histology and micro-PET-CT demonstrated that 18F-NaF uptake localized to areas of aneurysm disease and active calcification. Patients with aneurysms in the highest tertile of 18F-NaF uptake were more likely to experience AAA repair or rupture during follow-up. This PET-CT study of patients with asymptomatic AAA demonstrates that 18F-NaF uptake identifies advanced aneurysmal disease and is associated with aneurysm growth and clinical AAA events independent of established clinical risk factors.

Guo et al. (Hypertension. 2017 January; 69(1):102-108.) prospectively evaluate association of aortic calcification burden with progression of arterial stiffness in population-based samples of healthy middle-aged men. Aortic calcification was evaluated from level of aortic arch to iliac bifurcation. Arterial stiffness progression was measured as annual change in brachial-ankle pulse wave velocity. Aortic calcification had a positive and significant association with brachial-ankle pulse wave velocity after adjusting for age, race, mean arterial pressure, and heart rate. Annual change in aortic calcification was positively and significantly associated with arterial stiffness progression. In the subgroup of participants with prevalent aortic calcification at baseline, an increase in aortic calcification over the follow-up period was also significantly associated with greater arterial stiffness progression. The findings suggest that aortic calcification may be causally linked to arterial stiffness.

Marwick et al. (Kidney Int. 2019 October; 96(4):836-849.) reviews valvular heart disease in chronic kidney disease. Valvular heart disease (VHD) is highly prevalent in patients with chronic kidney disease (CKD) and end-stage kidney disease. The first detectable stage of VHD involvement in CKD is calcification. Calcification of the interstitial cells of the valve leaflets (and the annulus and subvalvular apparatus of the mitral valve) are the unifying pathophysiological features of valvular stenosis and/or insufficiency secondary to CKD and end-stage kidney disease (ESKD). Among patients undergoing long-term dialysis, the number of calcified valves is associated with all-cause mortality and cardiovascular death. Valvular calcification is an important contributor to VHD among patients with CKD and ESKD, particularly among patients with rapidly progressive aortic stenosis. Delaying the onset of valvular calcification may be a means of delaying the development or progression of VHD.

Mizobuchi et al. (J Am Soc Nephrol. 2009 July; 20(7):1453-64.) reviews vascular calcification in chronic kidney disease. Cardiovascular complications are the leading cause of death in patients with chronic kidney disease (CKD). A study demonstrated that the extent and histoanatomic type of vascular calcification are predictors of subsequent vascular mortality. Studies in VSMCs showed (Giachelli et al. Circ Res 96: 717-722, 2005; Chen et al., Kidney Int 62: 1724-1731, 2002) that high extracellular phosphate levels induce VSMCs to transform into osteoblast-like cells, suggesting that the processes of vascular calcification are active. The hemodynamic consequences of vascular calcification are the loss of arterial elasticity, increase in pulse wave velocity, development of left ventricular hypertrophy, decrease in coronary artery perfusion, and myocardial ischemia and failure.

Pikilidou et al. (J Vasc Res. 2015; 52(1):32-40.) reviews the contribution of osteoprogenitor cells to arterial stiffness and hypertension. Evidence shows that vascular calcification, either medial or intimal, induces arterial stiffening further worsening hypertension parallel to substantially increasing cardiovascular risk. Osteoprogenitor cells can derive from different cell types such as monocytes, pericytes and vascular smooth muscle cells (VSMCs) outside the bone microenviroment. The ectopic arterial calcium deposition is discriminated into medial and intimal and is predictive of cardiovascular morbidity and mortality. Mounting evidence supports (Altunkan et al., Eur J Intern Med 2005; 16: 580-584.) that arterial calcification largely affects arterial stiffness, a well-known consequence of vascular aging and the most important contributor to the development of hypertension and its detrimental consequences, namely stroke and myocardial infarction. There is a significant reverse association between pulse wave velocity, a reliable surrogate marker of cardiovascular risk, and cross-sectional cortical bone area in women, but not in men, after adjusting for confounders. The authors state that it is known by now that VC is associated with hypertension and that the onset of arterial calcification occurs at an earlier stage in hypertensive subjects. Moreover, it has been demonstrated that coronary artery calcification is associated with an increased occurrence of ischemic stroke in hypertensives. The mechanism behind this observation is that arterial calcification causes a progressive reduction in vascular resilience and compliance with a parallel increase in arterial stiffness, which is a major determinant of the rise in systolic blood pressure, the fall in diastolic BP and the acceleration of pulse wave velocity.

Conditions related to pathological calcium crystallization for which the compounds of the present invention are particularly useful include vascular calcification, coronary artery disease, vascular stiffening, valvular calcification, nephrocalcinosis, calcinosis cutis, kidney stones, chondrocalcinosis, osteoporosis, myocardial infarction, cardiovascular mortality (particularly in chronic kidney disease patients), progression of chronic kidney disease and failure of renal transplant grafts. Pathological crystallization has been shown to be associated with all-cause mortality of chronic kidney disease patients, hence the compounds of the present invention are indicated for chronic kidney disease patients in general.

Further conditions that will benefit from a treatment with the compounds of the invention are peripheral arterial disease, critical limb ischemia, calciphylaxis, general arterial calcification of infancy, aortic stenosis, atherosclerosis, pseudogout, primary hyperoxaluria and pseudoxanthoma elasticum.

In the context of the present specification, “peripheral arterial disease” refers to a narrowing of the peripheral arteries to the legs (most commonly), stomach, arms, and head. Symptoms include intermittent claudication (leg pain when walking which resolves with rest), skin ulcers, bluish skin, cold skin, or poor nail and hair growth.

In the context of the present specification, “critical limb ischemia” refers to a severe obstruction of the arteries which markedly reduces blood flow to the extremities, and progresses to the point of severe pain and even skin ulcers, sores, or gangrene. Critical limb ischemia is a very severe condition of peripheral artery disease.

In the context of the present specification, “calciphylaxis” or “calcific uremic arteriolopathy” relates to a syndrome of vascular calcification, thrombosis and skin necrosis.

In the context of the present specification, “pseudogout”, also known as “Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease” or “pyrophosphate arthropathy ” relates to a rheumatologic disorder believed to be caused by calcium pyrophosphate crystal accumulation in connective tissues, particularly joints such as the knee joint.

In the context of the present specification, the term “general arterial calcification of infancy” (GACI) relates to a disorder affecting the circulatory system that becomes apparent before birth or within the first few months of life, and which is characterized by abnormal calcification of the arteries and thickening of the arterial walls. These changes lead to stenosis and stiffness of the arteries, resulting in heart failure in some affected individuals, with signs and symptoms including difficulty breathing, edema, cyanosis, hypertension and cardiomegaly.

Some degree of flexibility exists as to the optimal composition of the anionic binding moiety as well as that of the polymeric solubility function. Without wanting to be bound by theory, the inventors hypothesize that this is due to the fact that the interactions that provide the therapeutic benefit mainly consist of electrostatic interactions between small anions and cations in combination with steric hindrance, and both phenomena are, in terms of requirement of fit of molecular interaction, less selective than e.g. a protein-ligand interaction.

In certain embodiments, R¹ is R² and the compound described above is used for treatment of any of the indications listed above.

In certain embodiments, R¹ is or comprises a polyethylene glycol or a polyglycerol, and R¹ has a molar mass between 100 g/mol and 3000 g/mol, particularly between 100 g/mol and 2500 g/mol, more particularly of approx. 100 g/mol to 2000 g/mol, and the compound is used for treatment of any of the indications listed above.

In certain embodiments, R¹ is or comprises a polyethylene glycol or a polyglycerol, and R¹ has a molar mass between 200 g/mol and 3000 g/mol, particularly between 300 g/mol and 2500 g/mol, more particularly of approx. 400 g/mol to 2000 g/mol, and the compound is used for treatment of any of the indications listed above.

In certain embodiments, the compound is described by a general formula (II)

wherein

-   -   one or two or three X are R¹ and the remaining X independently         from any other X can be OPO₃ ²⁻, OPSO₂ ²⁻, and OSO₃ ⁻ and     -   R¹ is a polyethylene glycol or a polyglycerol;         and the compound is used for treatment of any of the indications         listed above.

The straight lines in formula II are meant to indicate that the stereochemistry of the individual ring carbon atoms is undefined. The formula is meant to encompass any diastereomer.

In certain embodiments, R¹ is a polyethylene glycol.

In certain embodiments, R¹ is a polyethylene glycol described by a formula R³—(O—CH₂—CH₂)_(n)— or R³—(O—CH₂—CH₂)_(n)—O— and R³ is hydrogen, methyl or ethyl, and n has a value from 2 to 200.

In certain embodiments, n has a value from 3 to 200.

In certain embodiments, n has a value from 3 to 20. In certain embodiments, n has a value from 10 to 30. In certain embodiments, n has a value from 9 to 45.

In certain embodiments, n has a value from 7 to 11.

In certain embodiments, n has a value of 2. In certain embodiments, n has a value of 7. In certain embodiments, n has a value of 9. In certain embodiments, n has a value of 11. In certain embodiments, n has a value of 45.

In certain embodiments, the compound is described by the general formula (II), one X is R¹ and the remaining X independently from any other X can be OPO₃ ²⁻, OPSO₂ ²⁻, and OSO₃ ⁻; and R¹ is a polyethylene glycol or a polyglycerol having a molar mass between 100 g/mol and 3000 g/mol, particularly between 100 g/mol and 2500 g/mol, more particularly of approx. 100 g/mol to 2000 g/mol, and the compound is used for treatment of any of the indications listed above.

In certain embodiments, the compound is described by the general formula (II), one X is R¹ and the remaining X independently from any other X can be OPO₃ ²⁻, OPSO₂ ²⁻, and OSO₃ ⁻; and R¹ is a polyethylene glycol or a polyglycerol having a molar mass between 200 g/mol and 3000 g/mol, particularly between 300 g/mol and 2500 g/mol, more particularly of approx. 400 g/mol to 2000 g/mol, and the compound is used for treatment of any of the indications listed above.

In certain embodiments, the compound is described by the general formula (II), wherein

-   -   one X is R¹ and the remaining X are OPO₃ ²⁻; and     -   R¹ is a polyethylene glycol and has a molar mass between 100         g/mol and 3000 g/mol, particularly between 100 g/mol and 2500         g/mol, more particularly of approx. 100 g/mol or of approx. 2000         g/mol;         and the compound is used for treatment of any of the indications         listed above.

In certain embodiments, the compound is described by the general formula (II), wherein

-   -   one X is R¹ and the remaining X are OPO₃ ²⁻; and     -   R¹ is a polyethylene glycol and has a molar mass between 200         g/mol and 3000 g/mol, particularly between 300 g/mol and 2500         g/mol, more particularly of approx. 400 g/mol or of approx. 2000         g/mol;         and the compound is used for treatment of any of the indications         listed above.

In certain embodiments, the compound is described by the general formula (II) and

-   -   two X are R¹ and the remaining X independently from any other X         can be OPO₃ ²⁻, OPSO₂ ²⁻, and OSO₃ ⁻; and     -   each R¹ independently from the other is selected from a         polyethylene glycol and a polyglycerol;         and the compound is used for treatment of any of the indications         listed above.

In certain embodiments, the compound is described by the general formula (II), two X are R¹ and the remaining X independently from any other X can be OPO₃ ²⁻, OPSO₂ ²⁻, and OSO₃ ⁻; and each R¹ independently from the other is a polyethylene glycol or a polyglycerol having a molar mass between 100 g/mol and 3000 g/mol, particularly between 100 g/mol and 2500 g/mol, more particularly of approx. 100 g/mol to 2000 g/mol, and the compound is used for treatment of any of the indications listed above.

In certain embodiments, the compound is described by the general formula (II), two X are R¹ and the remaining X independently from any other X can be OPO₃ ²⁻, OPSO₂ ²⁻, and OSO₃ ⁻; and each R¹ independently from the other is a polyethylene glycol or a polyglycerol having a molar mass between 200 g/mol and 3000 g/mol, particularly between 300 g/mol and 2500 g/mol, more particularly of approx. 400 g/mol to 2000 g/mol, and the compound is used for treatment of any of the indications listed above.

In certain embodiments, the compound is described by the general formula (II), wherein

-   -   two X are R¹ and the remaining X are OPO₃ ²⁻; and     -   R¹ is a polyethylene glycol and has a molar mass         -   between 100 g/mol and 3000 g/mol, particularly between 100             g/mol and 2500 g/mol, more particularly of approx. 100 g/mol             or of approx. 2000 g/mol or         -   between 200 g/mol and 3000 g/mol, particularly between 300             g/mol and 2500 g/mol, more particularly of approx. 400 g/mol             or of approx. 2000 g/mol;             and the compound is used for treatment of any of the             indications listed above.

In certain embodiments, the compound is described by the general formula (II), wherein

-   -   two X are R¹ and the remaining X are OPSO₂ ²⁻; and     -   R¹ is a polyethylene glycol and has a molar mass         -   between 100 g/mol and 3000 g/mol, particularly between 100             g/mol and 2500 g/mol, more particularly of approx. 100 g/mol             or of approx. 2000 g/mol or         -   between 200 g/mol and 3000 g/mol, particularly between 300             g/mol and 2500 g/mol, more particularly of approx. 400 g/mol             or of approx. 2000 g/mol;

and the compound is used for treatment of any of the indications listed above.

In certain embodiments, the compound is described by the general formula (II), wherein

-   -   two X are R¹ and the remaining X are OSO₃ ⁻; and     -   R¹ is a polyethylene glycol and has a molar mass         -   between 100 g/mol and 3000 g/mol, particularly between 100             g/mol and 2500 g/mol, more particularly of approx. 100 g/mol             or of approx. 2000 g/mol or         -   between 200 g/mol and 3000 g/mol, particularly between 300             g/mol and 2500 g/mol, more particularly of approx. 400 g/mol             or of approx. 2000 g/mol;             and the compound is used for treatment of any of the             indications listed above.

In certain embodiments, the compound is described by the general formula (II) and

-   -   three X are R¹ and the remaining X independently from any other         X can be OPO₃ ²⁻, OPSO₂ ²⁻, and OSO₃ ⁻; and     -   each R¹ independently from the other is selected from a         polyethylene glycol and a polyglycerol;         and the compound is used for treatment of any of the indications         listed above.

In certain embodiments, the compound is described by the general formula (II), three X are R¹ and the remaining X independently from any other X can be OPO₃ ²⁻, OPSO₂ ²⁻, and OSO₃ ⁻; and each R¹ independently from the other is a polyethylene glycol or a polyglycerol having a molar mass

-   -   between 100 g/mol and 3000 g/mol, particularly between 100 g/mol         and 2500 g/mol, more particularly of approx. 100 g/mol to 2000         g/mol, or     -   between 200 g/mol and 3000 g/mol, particularly between 300 g/mol         and 2500 g/mol, more particularly of approx. 400 g/mol to 2000         g/mol;         and the compound is used for treatment of any of the indications         listed above.

In certain embodiments, the compound is described by the general formula (II), wherein

-   -   three X are R¹ and the remaining X are OPO₃ ²⁻; and     -   R¹ is a polyethylene glycol and has a molar mass         -   between 100 g/mol and 3000 g/mol, particularly between 100             g/mol and 2500 g/mol, more particularly of approx. 100 g/mol             or of approx. 2000 g/mol or         -   between 200 g/mol and 3000 g/mol, particularly between 300             g/mol and 2500 g/mol, more particularly of approx. 400 g/mol             or of approx. 2000 g/mol;             and the compound is used for treatment of any of the             indications listed above.

In certain embodiments, the compound is described by the general formula (II), wherein

-   -   three X are R¹ and the remaining X are OPSO₂ ²⁻; and     -   R¹ is a polyethylene glycol and has a molar mass         -   between 100 g/mol and 3000 g/mol, particularly between 100             g/mol and 2500 g/mol, more particularly of approx. 100 g/mol             or of approx. 2000 g/mol or         -   between 200 g/mol and 3000 g/mol, particularly between 300             g/mol and 2500 g/mol, more particularly of approx. 400 g/mol             or of approx. 2000 g/mol;             and the compound is used for treatment of any of the             indications listed above.

In certain embodiments, the compound is described by the general formula (II), wherein

-   -   three X are R¹ and the remaining X are OPO₃ ²⁻; and     -   R¹ is a polyethylene glycol and has a molar mass         -   between 100 g/mol and 3000 g/mol, particularly between 100             g/mol and 2500 g/mol, more particularly of approx. 100 g/mol             or of approx. 2000 g/mol or         -   between 200 g/mol and 3000 g/mol, particularly between 300             g/mol and 2500 g/mol, more particularly of approx. 400 g/mol             or of approx. 2000 g/mol;             and the compound is used for treatment of any of the             indications listed above.

In certain embodiments, the compound is characterized by a general formula (III a), (III b), (III c) or (III d):

wherein each X (independently) and R¹ have the meaning outlined above and the compound is used for treatment of any of the indications listed above.

In certain embodiments, the compound is characterized by a general formula (III e), (III f), (III g), (III h), (III i) or (III j):

wherein R¹ has the meaning outlined above and the compound is used for treatment of any of the indications listed above.

In certain embodiments, more than one R¹ is present and each R¹ is the same as any other R¹.

In certain embodiments, the compound is characterized by a general formula (IV a), (IV b), (IV c), (IV d), (V a) or (V b)

wherein each X (independently) and R¹ have the meaning outlined above and the compound is used for treatment of any of the indications listed above.

In certain embodiments, one or two or three X are R¹ and the remaining X are

-   -   all OPO₃ ²⁻ or     -   all OPSO₂ ²⁻ or     -   all OSO₃ ⁻.

In certain embodiments,

-   -   one or two or three X are R¹ and the remaining X are OPO₃ ²⁻;         and     -   R¹ is a polyethylene glycol and has a molar mass between 100         g/mol and 3000 g/mol, particularly between 100 g/mol and 2500         g/mol, more particularly of approx. 100 g/mol or of approx. 2000         g/mol.

In certain embodiments,

-   -   one or two or three X are R¹ and the remaining X are OPSO₂ ²⁻;         and     -   R¹ is a polyethylene glycol and has a molar mass between 100         g/mol and 3000 g/mol, particularly between 100 g/mol and 2500         g/mol, more particularly of approx. 100 g/mol or of approx. 2000         g/mol.

In certain embodiments, three X are R¹.

In certain embodiments, one X is R¹ and of the remaining X

-   -   three X are OSO₃ ⁻ and two X are OPSO₂ ²⁻, or three X are OSO₃ ⁻         and two X are OPO₃ ²⁻, and     -   R¹ is a polyethylene glycol and has a molar mass between 100         g/mol and 3000 g/mol, particularly between 100 g/mol and 2500         g/mol, more particularly of approx. 100 g/mol or of approx. 2000         g/mol.

In certain embodiments, R¹ is or comprises a polyethylene glycol characterized by a formula R³—(O—CH₂—CH₂)_(n)— or R³—(O—CH₂—CH₂)_(n)—O— and R³ is hydrogen, methyl or ethyl.

In certain embodiments, the compound is described by a general formula (III k), (III l), (III m) or (III n)

wherein n has a value from 2 to 200. In certain embodiments, n is 2 or n is 7 to 50. In certain embodiments, n is 2, 7 to 12 or 40 to 50. In certain embodiments, n is 2, 7, 9, 11 or 45. The compound is used for treatment of any of the indications listed above.

In certain embodiments, the compound is described by a general formula (III k), (III l), (III m) or (III n), wherein n has a value from 3 to 200, particularly 7 to 50, more particularly 7 to 12 or 40 to 50, even more particularly 9 or 45, and the compound is used for treatment of any of the indications listed above.

In certain embodiments, the compound is described by any one of formulae (III o), (III p), (III q), (III r), (III s), (III t), (III u), (III v), (III w), (III x), (III y) or (III z)

and the compound is used for treatment of any of the indications listed above.

With regard to the substituents (OPO₃ ²⁻, OPSO₂ ²⁻, OSO₃ ⁻) and the length of the PEG moieties,

-   -   formula (III m) with n=2 corresponds to formula (III o)/compound         INS-2001;     -   formula (III m) with n=7 corresponds to formula (III p)/compound         INS-2031;     -   formula (III m) with n=11 corresponds to formula (III         q)/compound INS-2041;     -   formula (III n) with n=2 corresponds to formula (III u)/compound         INS-4001;     -   formula (III n) with n=7 corresponds to formula (III v)/compound         INS-4031; and     -   formula (III n) with n=11 corresponds to formula (III         w)/compound INS-4041.

In certain embodiments, the compound is described by a general formula (IV e) or (V c)

wherein n has a value from 2 to 200, particularly 2 or 7 to 50, more particularly 2, 7 to 12 or 40 to 50, even more particularly 2, 7, 9, 11 or 45, and the compound is used for treatment of any of the indications listed above.

One embodiment of the invention that shows a particularly high activity is the use of 2-PEG-IP5 (myo-pentakis-inositolphosphate-(2)-PEG, specified by formula (IV e) with PEG moieties having a molar mass of approximately 400 g/mol (n=9) or approximately 2000 g/mol (n=45) for the indications listed above. This conclusion is drawn from the results of an in vitro assay that measures the propensity for calcification of human serum, which has been clinically validated as a predictor of all-cause mortality in CKD patients and renal transplant patients (FIG. 1). The inventors show that surprisingly, IP5-PEG is a much more potent inhibitor than IP6 in reducing the propensity for calcification of human serum. The result is unexpected because the removal of a phosphate group is presumed to reduce the molecule's affinity for calcium but this is evidently more than compensated for by the addition of the PEG moiety. Without wanting to be bound by theory, the inventors hypothesize that this is due to the fact that the PEG moiety increases the solubility of CPP complexes and provides steric hindrance that prevents the transformation from amorphous to crystalline calcium phosphate and/or crystal growth. Furthermore, adding a PEG (or another polymer) moiety to the molecule offers the possibility to tailor its circulation time and hence offers more flexible dosing schedules than IP6. This aspect has not been considered for IP6 analogues previously and presents a competitive advantage over IP6 for the present indication.

In certain embodiments, the compound is described by any one of formulae (IV f), (IV g), (IV h), (IV i), (IV j), (IV k), (V d), (V e), (V f), (V g), (V h) or (V i)

With regard to the substituents (OPO₃ ²⁻, OPSO₂ ²⁻, and OSO₃ ⁻) and the length of the PEG moieties,

-   -   formula (IV e) with n=2 corresponds to formula (IV f)/compound         1;     -   formula (IV e) with n=7 corresponds to formula (IV g)/compound         INS-3031;     -   formula (IV e) with n=11 corresponds to formula (IV h)/compound         INS-3041;     -   formula (V c) with n=2 corresponds to formula (V d)/compound         INS-5001;     -   formula (V c) with n=7 corresponds to formula (V e)/compound         INS-5031; and     -   formula (V c) with n=11 corresponds to formula (V f)/compound         INS-5041.

In certain embodiments, wherever a polyethylene glycol chain is shown as a formula in the present specification, the PEG moiety is a monodisperse polyethylene glycol. In certain formulae, a monodisperse PEG moiety is assigned the abbreviation mdPEG.

In certain embodiments, the compound is described by a general formula (III o), (III p), (III q), (III u), (III v) or (III w)

In certain embodiments,

-   -   a) (p+q) is 0, two out of five X are independently selected from         OPO₃ ²⁻ and OPSO₂ ²⁻ and the remaining X are OSO₃ ⁻, or     -   b) (p+q) is 0, three out of five X are independently selected         from OPO₃ ²⁻ and OPSO₂ ²⁻ and the remaining X are OSO₃ ⁻, or     -   c) (p+q) is 1, two out of six X are independently selected from         OPO₃ ²⁻ and OPSO₂ ²⁻ and the remaining X are OSO₃ ⁻, or     -   d) (p+q) is 1, three out of six X are independently selected         from OPO₃ ²⁻ and OPSO₂ ²⁻ and the remaining X are OSO₃ ⁻, or     -   e) (p+q) is 1, four out of six X are independently selected from         OPO₃ ²⁻ and OPSO₂ ²⁻ and the remaining X are OSO₃ ⁻, or     -   f) (p+q) is 2, three out of seven X are independently selected         from OPO₃ ²⁻ and OPSO₂ ²⁻ and the remaining X are OSO₃ ⁻, or     -   g) (p+q) is 2, four out of seven X are independently selected         from OPO₃ ²⁻ and OPSO₂ ²⁻ and the remaining X are OSO₃ ⁻ or     -   h) (p+q) is 2, five out of seven X are independently selected         from OPO₃ ²⁻ and OPSO₂ ²⁻ and the remaining X are OSO₃ ⁻;         and the compound is used for treatment of any of the indications         listed above.

In certain embodiments, the compound is described by formula

and is used for treatment of any of the indications listed above.

FIG. 1 demonstrates that this compound (4,6-di-(O-thiophosphate)-inositol-1,2,3,5-tetra-O-sulfate, IT2S4) is more active than IP6 in inhibiting the transition of primary to secondary CPPs and thus can reduce the propensity for calcification of human serum.

In certain embodiments, the compound is described by formula

and is used for treatment of any of the indications listed above.

FIG. 1 demonstrates that this compound (4,6-di-(O-phosphate)-inositol-1,2,3,5-tetra-O-sulfate, IP2S4) is more active than IP6 in inhibiting the transition of primary to secondary CPPs and thus can reduce the propensity for calcification of human serum.

According to a second aspect of the invention, a dosage form comprising the compound as specified by any of the above formulae is provided for use in therapy or prevention of conditions related to pathological calcium crystallization.

The dosage form may be formulated for parenteral administration, such as intravenous, intraperitoneal, intramuscular, intra-arterial or subcutaneous administration. Optionally, a pharmaceutically acceptable carrier and/or excipient may be present.

According to a third aspect of the invention, a dialysis solution for use in hemodialysis, hemofiltration or peritoneal dialysis comprising the compound as specified in the above aspects of the invention is provided for use in therapy or prevention of conditions related to pathological calcium crystallization.

According to another aspect of the invention, a method of treatment or prevention of any of the conditions related to pathological calcium crystallization listed above is provided, comprising the administration of the compound as specified by any of the above formulae to a subject in need thereof.

The compound may be administered intravenously, intraperitoneally, intramuscularly, intra-arterially or subcutaneously. Alternatively, the compound may be administered as a component of a haemodialysis or peritoneal dialysis solution.

Compound Claims

According to yet another aspect of the invention, a compound according to general formula (II) is provided, wherein

-   -   two or three X are R¹ and the remaining X independently from         other X are selected from OPO₃ ²⁻, OPSO₂ ²⁻, and OSO₃ ⁻; and     -   R¹ is a polyethylene glycol or a polyglycerol.

In certain embodiments of this aspect of the invention, two or three X are R¹ and the remaining X are

-   -   all OPO32- or     -   all OPSO22- or     -   all OSO3-.

In certain embodiments of this aspect of the invention, R¹ is a polyethylene glycol and has a molar mass between 100 g/mol and 3000 g/mol, particularly between 100 g/mol and 2500 g/mol, more particularly of approx. 100 g/mol to 2000 g/mol.

Another aspect of the invention relates to a compound described by any one of formulae (IV a), (IV b), (IV c), (IV d), (V a) or (V b), wherein each X (independently) and R¹ have the meaning outlined above. In certain embodiments of this aspect of the invention, n (as part of the definition of R¹) has a value from 2 to 200. In certain embodiments of this aspect of the invention, n is 2 or n is 7 to 50. In certain embodiments of this aspect of the invention, n is 2, 7 to 12 or 40 to 50. In certain embodiments of this aspect of the invention, n is 2, 7, 9, 11 or 45.

In certain embodiments, the compound of the invention is described by any one of formulae (IV e) or (V c), and n has a value from 2 to 200. In certain embodiments of this aspect of the invention, n is 2 or n is 7 to 50. In certain embodiments of this aspect of the invention, n is 2, 7 to 12 or 40 to 50. In certain embodiments of this aspect of the invention, n is 2, 7, 9, 11 or 45.

In certain embodiments of this aspect of the invention, all X except the two or three X that are R¹ are phosphate.

In certain embodiments of this aspect of the invention, R¹ is a polyethylene glycol.

In certain embodiments of this aspect of the invention, R¹ has a molar mass between 100 g/mol and 3000 g/mol, particularly between 100 g/mol and 2500 g/mol, more particularly of approx. 100 g/mol to 2000 g/mol.

In certain embodiments of this aspect of the invention of this aspect of the invention, R¹ has a molar mass between 200 g/mol and 3000 g/mol, particularly between 300 g/mol and 2500 g/mol, more particularly of approx. 400 g/mol to 2000 g/mol.

Another aspect of the invention relates to a compound described by any one of formulae (IV f), (IV g), (IV h), (IV i), (IV j), (IV k), (V d), (V e), (V f), (V g), (V h) or (V i).

Any novel compound or compound group described herein is provided per se. It may be used advantageously as a medicament in the treatment of pathological crystallization and the specific medical uses provided herein.

The compound, dosage form or composition according to any one of the preceding claims for use in a condition related to pathological calcium crystallisation, wherein said condition is selected from vascular calcification, coronary artery disease, vascular stiffening, valvular calcification, nephrocalcinosis, calcinosis cutis, kidney stones, chondrocalcinosis, osteoporosis, myocardial infarction, cardiovascular mortality, progression of chronic kidney disease, failure of renal transplant grafts and peripheral arterial disease, critical limb ischemia, calciphylaxis, general arterial calcification of infancy and aortic stenosis, atherosclerosis, pseudogout, primary hyperoxaluria and pseudoxanthoma elasticum.

The compounds disclosed herein may be present in any form commonly used in pharmaceutical technology. Particular embodiments include, but are not limited to, the sodium salt, magnesium salt, potassium salt, ammonium salt, free acid, or a mixture of the preceding forms. Other pharmaceutically acceptable salts are known to the skilled artisan and can be obtained, inter alia, from Haynes et al., J. Pharmaceutical Sci. 94, 2005 2111-2120, DOI 10.1002/jps.20441

Terms and Definitions

In the context of the present specification, a monodisperse polyethlylene glycol (mdPEG) is a PEG that has a single, defined chain length and molecular weight. mdPEGs are typically generated by separation from the polymerization mixture by chromatography.

Wherever alternatives for single separable features are laid out herein as “embodiments”, it is to be understood that such alternatives may be combined freely to form discrete embodiments of the invention disclosed herein.

The invention is further illustrated by the following examples and figures, from which further embodiments and advantages can be drawn. These examples are meant to illustrate the invention but not to limit its scope.

EXAMPLES

TABLE 1 Compounds No. of M_(w) of PEG Substituents Com- For- PEG (mono- M_(w) of other than pound mula tails disperse) compound PEG INS-2001 III o 1 100 672.11 5 × OPO₃ ²⁻ INS-2031 III p 1 320 892.37 5 × OPO₃ ²⁻ INS-2041 III q 1 500 1068.59 5 × OPO₃ ²⁻ INS-2042 1 550 1112.64 5 × OPO₃ ²⁻ (polydisp.) INS-2101 III r 1 100 752.41 5 × OPSO₂ ²⁻ INS-2131 III s 1 320 972.68 5 × OPSO₂ ²⁻ INS-2141 III t 1 500 1148.89 5 × OPSO₂ ²⁻ INS-4001 III u 1 100 675.37 2 × OPO₃ ²⁻, 3 × OSO³⁻ INS-4031 III v 1 320 895.63 2 × OPO₃ ²⁻, 3 × OSO³⁻ INS-4041 III w 1 500 1071.84 2 × OPO₃ ²⁻, 3 × OSO³⁻ INS-4101 III x 1 100 707.49 2 × OPSO₂ ²⁻, 3 × OSO³ INS-4131 III y 1 320 927.75 2 × OPSO₂ ²⁻, 3 × OSO³ INS-4141 III z 1 500 1103.96 2 × OPSO₂ ²⁻, 3 × OSO³ INS-3001 IV f 2 100 696.28 4 × OPO₃ ²⁻ INS-3031 IV g 2 320 1136.81 4 × OPO₃ ²⁻ INS-3041 IV h 2 500 1489.23 4 × OPO₃ ²⁻ INS-3101 IV i 2 100 760.52 4 × OPSO₂ ²⁻ INS-3131 IV j 2 320 1201.05 4 × OPSO₂ ²⁻ INS-3141 IV k 2 500 1553.48 4 × OPSO₂ ²⁻ INS-5001 V d 3 100 720.45 3 × OPO₃ ²⁻ INS-5031 V e 3 320 1381.24 3 × OPO₃ ²⁻ INS-5041 V f 3 500 1909.88 3 × OPO₃ ²⁻ INS-5101 V g 3 100 768.63 3 × OPSO₂ ²⁻ INS-5131 V h 3 320 1429.42 3 × OPSO₂ ²⁻ INS-5141 V i 3 500 1958.06 3 × OPSO₂ ²⁻

Calcification Assay

The inventors performed an in vitro assay that measures the propensity for calcification of human serum and has been clinically validated as a predictor of all-cause mortality in CKD patients and renal transplant recipients (as described in Pasch, Journal of the American Society of Nephrology 23, 1744-1752, 2012). The experiment was carried out by mixing a calcium solution, human pooled serum, the test compound at the final concentration indicated and a phosphate solution, and the transition time of primary to secondary CPPs was measured at 37° C. using a nephelometer for up to 600 minutes.

The data of FIG. 1 show that the compounds IP2S4 and IT2S4 are more active than IP6. Furthermore, compound 2-PEG-IP5 is far more active than any other compound in this assay. This result suggests a key role of the polymer moiety in preventing the transition of primary to secondary CPPs and in reducing the propensity for calcification of human serum.

The data of FIG. 2 show that the compounds INS-2031 (III p), INS-3001 (IV f) and INS-3031 (IV g) are more active than IP6. The compounds having two PEG moieties (INS-3001, INS-3031) are more active than the compounds having one PEG moiety (INS-2031). This result suggests a key role of the polymer moiety in preventing the transition of primary to secondary CPPs and in reducing the propensity for calcification of human serum.

Synthesis of IT2S4 (VI a)

The synthesis followed the sequence depicted in the scheme below:

Phosphorylation

The known 2-tertbutyldimethylsilyl inositol orthoformate was co-evaporated 3× with toluene and dissolved in dichloromethane (DCM). 1H-tetrazole (4 eq.) followed by phosphoramidite (8 eq.) were added to the reaction and stirred overnight. Pyridine, followed by crushed sulphur flakes (20 eq.) were added to the reaction and stirred overnight. The resulting crude mixture was diluted with DCM and washed with saturated NaHCO₃, dried with Na₂SO₄, filtered and concentrated. The product was purified by flash chromatography with DCM in toluene.

¹H-NMR (400 MHz; CDCl3): δ 7.35-7.29 (m, 4H), 7.15 (dd, J=6.6, 2.1 Hz, 2H), 7.07-7.04 (m, 2H), 5.54 (d, J=1.1 Hz, 1H), 5.45-5.41 (m, 2H), 5.30-4.97 (m, 8H), 4.51-4.49 (m, 1H), 4.33-4.32 (m, 2H), 4.27 (d, J=1.3 Hz, 1H), 0.93 (s, 9H), 0.13 (s, 6H);

³¹P-NMR (162 MHz; CDCl3): δ 70.1;

Deprotection

The following deprotection conditions are in analogy to the synthesis published in the Journal of the American Chemical Society (JACS 2005, 127, 5288).

Starting material (50mg) was treated with thiophenol (300 μl), m-cresol (300 μI), trifluoroacetic acid (1.8 ml). Trimethylsilyl bromide (TMSBr) was then added slowly (360 μl). The mixture was stirred 2 h at room temperature. And then evaporated twice from toluene. The crude residue was diluted with DCM, and ca. 5 ml water and neutralized with 1N NaOH. The aqueous layer (slightly cloudy) was poured directly on SolEx C18 cartridge (Thermofisher, 1 g, 6 ml) and eluted with water. In some cases some aromatic impurities were found in the final product but would precipitate over time in water and could be filtered-off.

¹H-NMR (500 MHz; D₂O): δ 4.36 (q, J=9.6 Hz, 2H), 4.02 (t, J=2.7 Hz, 1H), 3.64 (dd, J=9.7, 2.8 Hz, 2H), 3.50 (t, J=9.3 Hz, 1H).

³¹P-NMR (203 MHz; D₂O): δ 45.7

Sulfation

The sulfation reaction of the thiophosphate has to be performed carefully because the thiophosphate is eventually converted to the phosphate under the reaction conditions. We thus monitored the sulfation carefully and saw that the reaction was complete after ca. 30 min. and that no decomposition could be observed in this time. Thus, sulphurtrioxide dimethylformamide (SO₃-DMF) complex (12 eq.) was added to a suspension of inositol phosphate in DMF and the reaction was stirred 35 min. The reaction was quenched by adding 1N NaOH, until ca. pH 8 followed by ca. 3 ml methanol (MeOH) to precipitate salts. The solid was purified by Sephadex LH-20 column, eluting with water.

¹H-NMR (500 MHz; D₂O): δ 5.06 (s, 1H), 5.04-4.98 (m, 4H), 4.79-4.76 (m, 1H).

³¹P-NMR (203 MHz; D₂O): δ 44.5

Synthesis of IP2S4 (VI c)

The synthesis followed the sequence depicted in the scheme below:

Hydrolysis

4,6-Di-O-phosphate-myo-inositol (2)

2-O-Tert-butyldimethylsilyl-1,3,5-orthoformate-4,6-(O-dixylylenephospho)-myo-inositol (1.00 g, 1.5 mmol, 1 eq.) in methanol/dichloromethane (MeOH/DCM) 30% (30m1, 0.05 M) was treated with trimethylsilyl bromide (TMSBr) (11 ml, 83.8 mmol, 56 eq.) and stirred for 5 h. The reaction mixture was degased with N₂ and the HBr was neutralized with 1 M NaOH solution. After 1-2 h it was concentrated to dryness. The crude was washed twice with acetone and twice with acetonitrile (ACN) to give 2 as a white solid (539 mg, quantitative yield).

¹H-NMR (400 MHz, MeOD): δ (ppm)=4.40 (q, 3JHH=9.1 Hz, 2JHP=9.1 Hz, 2H, H—C4/6), 4.01 (t, J=2.6 Hz, 1H, H—C2), 3.63 (dd, J=9.68, 2.76 Hz, 2H, H—C1/3), 3.61 (t, J=9.27 Hz, 1H, H—C5);

³¹P-NMR (160 MHz,1H- decoupled, MeOD): δ (ppm)=1.15 (P-C4/6); 13CNMR (150 MHz, MeOD): δ (ppm)=81.28 (d, 2JCP=6.1 Hz, 2 C, C4/6), 74.12 (t, 3JCP=3.8 Hz, 1 C, C5), 73.75 (s, 1 C, C2), 72.13 (d, 3JCP=3.2 Hz, 2 C, C1/3); [m/z (ESI) (M+H)+ C6H15O12P2 required 341.0033, found 341.0037].

Sulfation

1,2,3,5-Tetra-O-sulfonyl-4,6-(di-O-phosphate)-myo-inositol (1)

4,6-di-O-phosphate-myo-inositol (30 mg, 90 μmol, 1 eq.) was co-evaporated with toluene (3×) and dried under high vacuum for 1 h. Dry dimethylformamide (DMF) (1 ml, 0.09 M) was added and the reaction mixture was treated with SO₃-Et₃N (197 mg, 109 pmol, 12 eq.) and TfOH (190 μl, 215 μmol, 24 eq.). It was heated at 45° C. and stirred overnight. The reaction mixture was neutralized by addition of Et₃N (0.15 ml, 12 eq.). Immediately after the neutralization the mixture was diluted in nanopure water (2 ml) and loaded on a sephadex G10 column. 14 fractions of 3-4 ml were collected and put into the freeze-dryer overnight. Fractions 3-7 were combined to give 1 as a white solid (46.31 μmol, 51%).

¹H-NMR (400 MHz, D₂O): δ (ppm)=5.40 (br, 1H, H—C2), 4.64-4.44 (m, 5H, H—C1/3, H—C5, H—C4/6), 3.70 (s, 8H, internal standard dioxane), 3.15 (q, J=7.3 Hz, 6H, CH2-Et₃N), 1.23 (t, J=7.3 Hz, 9H, CH3-Et₃N).

Synthesis of PEG-IP5 (III o, III p, III q)

The synthesis followed the sequence depicted in the scheme below:

Inositol orthoformate was reacted with 1 eq. of PEG tosylate to the singly PEG-ylated 4- or 6-PEG inositol orthoformate. The orthoformate protection group was removed using trifluoroacetic acid and dichloromethane. The compound was reacted with phosphoramidite, 1H-tetrazole, dichloromethane and meta-chloroperoxybenzoic acid. The resulting compound was reacted with H₂, MeOH and PdO to 4-PEG-IP5 or 6-PEG-IP5, respectively.

Synthesis of 4,6-PEG- IP4 (IV f, IV g, IV h)

The synthesis followed the sequence depicted in the scheme below:

Inositol orthoformate was reacted with PEG tosylate to the doubly PEG-ylated 4,6-PEG inositol orthoformate. The orthoformate protection group was removed using trifluoroacetic acid and dichloromethane. The compound was reacted with phosphoramidite, 1H-tetrazole, dichloromethane and meta-chloroperoxybenzoic acid. The resulting compound was reacted with H₂, MeOH and PdO to 4,6-PEG-IP4

Synthesis of 4-PEG-IP253 (III u, III v, III w)

The synthesis followed the sequence depicted in the scheme below:

The known myo-inositol orthoformate can be mono alkylated with a commercial PEG tosylate in the presence of a strong based such as sodium hydride in DMF. The reaction mixture is then quenched with water and extracted with dichloromethane. The organic layer is dried and concentrated under reduced pressure. The product can be purified by silica gel chromatography. Phosphorylation of the free hydroxyl groups is done under standard conditions using a phosphoramidite reagent followed by oxidation with meta-chloroperbenzioc acid. The product can be purified by normal or reverse phase chromatography. The orthoester and phosphate groups are then deprotected concomitantly using excess bromotrimethylsilane in a mixture of methanol and dichloromethane. The product can be purified by precipitation or reverse phase chromatography. Sulfation of the free hydroxyl group is performed by suspending the product in dry DMF and reacting with excess sulfur trioxide-DMF complex. The reaction is then quenched with water and neutralized. The final product can be precipitated out of the reaction mixture by adding methanol and purified by size-exclusion chromatography or reverse phase chromatography.

Synthesis of PEG-IT5, 4,6-PEG-IT4 and PEG-IT2S3

The synthesis of PEG-IT5 (III r, III s, III t), 4,6-PEG-IT4 (IV i, IV j, IV k) and PEG-IT2S3 (III x, III y, III z) followed the sequences specified for PEGIP5, 4,6-PEG-IP4 and PEG-IP2S3, except that the phosphorylation was performed by addition of 1H tetrazole (4 eq.) followed by phosphoramidite (8 eq.)

to the reaction and stirred overnight. Afterwards, pyridine, followed by crushed sulphur flakes (20 eq.) were added to the reaction and stirred overnight to complete the thiophosphorylation.

Synthesis of 2,4,6-PEG-IP3 (V d, V e, V f)

The synthesis followed the sequence depicted in the scheme below:

Inositol orthoformate was reacted with PEG tosylate to the triple PEG-ylated 2,4,6-PEG inositol orthoformate. The orthoformate protection group was removed using trifluoroacetic acid and dichloromethane. The compound was reacted with phosphoramidite, 1H-tetrazole, dichloromethane and meta-chloroperoxybenzoic acid. The resulting compound was reacted with H2, MeOH and PdO to 2,4,6-PEG-IP4.

Synthesis of 2,4,6-PEG-IT3 (V g, V h, V i)

The synthesis of 2,4,6-PEG-IT3 followed that described for 2,4,6-PEG-IP3 except that the phosphorylation was performed by addition of 1 H tetrazole (4 eq.) followed by phosphoramidite (8 eq.) to the reaction and stirred overnight. Afterwards, pyridine, followed by crushed sulphur flakes (20 eq.) were added to the reaction and stirred overnight to complete the thiophosphorylation. 

We claim:
 1. A method for treatment of a condition associated with cardiovascular calcification, comprising administering to a subject in need thereof a compound described by a general formula (II)

wherein one or two or three X are R¹ and the remaining X independently from each other are selected from OPO₃ ²⁻, OPSO₂ ²⁻, and OSO₃ ⁻; and each R¹ independently of any other R¹ is a polyethylene glycol or a polyglycerol, and wherein the condition is selected from the group consisting of coronary artery disease, vascular stiffening, valvular calcification, myocardial infarction, cardiovascular mortality, progression of chronic kidney disease, peripheral arterial disease, critical limb ischemia, calciphylaxis, general arterial calcification of infancy, aortic stenosis, atherosclerosis, pseudoxanthoma elasticum, cardiac hypertrophy, heart failure, arrhythmia, aneurysm, valvular stenosis, aortic regurgitation, mitral stenosis, mitral regurgitation, stroke, and cognitive function.
 2. The method of claim 1, wherein the condition is selected from aortic stenosis and valvular calcification.
 3. The method of claim 1, wherein R¹ has a molar mass between 100 g/mol and 3000 g/mol.
 4. The method of claim 1, wherein the compound is characterized by a general formula III a, III b, III c or III d:

wherein each X (independently) and R¹ have the meaning outlined above.
 5. The method of claim 1, wherein more than one R¹ is present and each R¹ is the same as any other R¹.
 6. The method of claim 1, wherein the compound is characterized by a general formula (IV a), (IV b), (IV c), (IV d), (V a) or (V b)

wherein each X (independently) and R¹ have the meaning outlined above.
 7. The method of claim 1, wherein one or two or three X are R¹ and the remaining X are all OPO₃ ²⁻ or all OPSO2²⁻ or all OSO₃ ⁻.
 8. The method of claim 1, wherein one or two or three X are R¹ and the remaining X are OPO₃ ²⁻; and R¹ is a polyethylene glycol and has a molar mass between 100 g/mol and 3000 g/mol.
 9. The method of claim 1, wherein one or two or three X are R¹ and the remaining X are OPSO₂ ²⁻; and R¹ is a polyethylene glycol and has a molar mass between 100 g/mol and 3000 g/mol.
 10. The method of claim 1, wherein two X are R¹.
 11. The method of claim 1, wherein: one X is R¹ and of the remaining X: three X are OSO₃ ⁻ and two X are OPSO₂ ²⁻, or three X are OSO₃ ⁻ and two X are OPO₃ ²⁻, and R¹ is a polyethylene glycol and has a molar mass between 100 g/mol and 3000 g/mol.
 12. The method of claim 1, wherein R¹ is a polyethylene glycol characterized by a formula R³—(O—CH₂—CH₂)_(n)— or R³—(O—CH₂—CH₂)_(n)—O—, and R³ is hydrogen, methyl or ethyl.
 13. The method of claim 1, wherein the compound is described by a general formula (III k), (III I), (III m), (III n), (IV e) or (V c)

and wherein n has a value from 2 to 200 and R³ is selected from H, methyl and ethyl.
 14. The method of claim 1, wherein the compound is described by any one of formulae (III o), (III p), (III q), (III r), (III s), (III t), (III u), (III v), (III w), (III x), (III y), (III z), (IV f), (IV g), (IV h), (IV i), (IV j), (IV k), (V d), (V e), (V f), (V g), (V h) or (V i)


15. The method of claim 1, wherein said polyethylene glycol is a monodisperse polyethylene glycol.
 16. The method of claim 1, wherein the compound is described by any one of formulae (III o), (III p), (III q), (III u), (III v) or (III w)


17. A compound of general formula (II)

wherein three X are R¹ and the remaining X independently from each other X are selected from OPO₃ ²⁻, OPSO₂ ²⁻, and OSO₃ ⁻; and each R¹ independently of any other R¹ is a polyethylene glycol or a polyglycerol.
 18. The compound of claim 17, wherein the compound is any one of:

wherein each X (independently) and R¹ have the meaning outlined above.
 19. The compound of claim 17, wherein R¹ is a polyethylene glycol and has a molar mass between 100 g/mol and 3000 g/mol.
 20. The compound of claim 17 described by the formula (V c),

wherein n has a value from 2 to 200 and R³ is selected from H, methyl and ethyl.
 21. A composition comprising the compound of claim 16, wherein the composition is formulated for intravenous, intraperitoneal, intramuscular, intra-arterial, or subcutaneous administration.
 22. A composition comprising the compound of claim 16, wherein the composition is formulated as a haemodialysis or peritoneal dialysis solution. 